Analysis of demagnetization fault back-EMF of permanent magnet synchronous motor using mathematical model based on magnetic field superposition principle

摘要

According to magnetic field superposition principle and characteristic of square wave series, back-EMF of permanent magnet synchronous motor (PMSM) under demagnetization fault condition is decomposed into health component and demagnetization fault component. A operation of mathematical model of single slot and single phase no-load backEMF, when demagnetization fault of different degree occurred in any magnetic body, any single pole and any multiple pole, is presented. The back-EMF mathematical model and the finite element simulation model results for 42 kW - PMSM, which has 8 poles and V-shaped permanent magnet rotor structure are compared, that allowed to verify the mathematical model. The results show that the back-EMF waveform of the slot winding can reflect the specific position and the severity of the demagnetization poles. The single phase back-EMF waveform can reflect only demagnetization conditions of all poles, but can not identify the specific position of the demagnetization poles.